Key Concepts

* When building, design the facility with energy management in mind.

* Purchase energy-efficient products and maintain and commission systems to ensure optimum performance.

* Rebates and incentives from the local utility can help pay for new--and more efficient--equipment.

Building Automation Systems

CONSTRUCTING

Building automation systems (BASs) are computerized solutions that control HVAC and other equipment to ensure efficient and safe operation of the building. Often called "building integration" or "building controls," this solution can maximize the performance and energy efficiency of HVAC systems. Andrew Wilcox, global marketing manager, Trane Control Systems, St. Paul, MN, provides the following as examples of how optimization strategies can be implemented with BASs to reduce consumption and lead to potential savings:

* Chiller/tower optimization. A BAS calculates the cooling tower setpoint to minimize the sum of the chiller plus tower energy consumption, and reduces 5 to 7 percent of the chiller/ tower energy.

* Variable flow pump pressure optimization. A BAS reduces pump energy consumption by resetting the pump pressure control setpoint to a minimum as indicated by the position of the "critical" chilled water system control valve. It can reduce 20 to 45 percent of the pumping system energy.

* VAV fan pressure optimization. Building controls reduce fan energy consumption by resetting the fan pressure control setpoint to a minimum as indicated by the position of the "critical" damper, reducing 20 to 45 percent of the fan system energy.

* Ventilation reset. A BAS dynamically monitors the outdoor air fraction of each zone, calculates the minimum outdoor airflow rate that meets the ventilation requirements of each system, and resets the outdoor air dampers to bring in the proper ventilation airflow, which reduces up to 25 percent of energy used by the HVAC system.

When purchasing a BAS, make sure the company offering the solution has a solid understanding of the HVAC components being installed in the building. Wilcox cautions: "Facility managers and building owners should look for a supplier with experience in both controls and HVAC to have the application knowledge to effectively implement these energy-saving strategies."

HVAC is not the only equipment that can interface to a BAS. Security and life-safety equipment, as well as lighting systems and vertical transportation, can be tied in and programmed to provide an automatic sequence of events when the building is occupied. Rick LeBlanc, senior vice president and division head, building automation division, Siemens Building Technologies Inc., Buffalo Grove, IL, explains: "If you use your access-control card to go into a certain area of the building, the building automation system will turn on the air-conditioning and the lighting system. When the building is unoccupied, the building automation system can shut down or run on a night setback mode. When the first occupant comes in, that system re-energizes itself, thereby saving energy in an unoccupied period."